NetworkSocketAPI / DnsQuery

Library to resolve text URLs to IP addresses (IPv4)

Dependents:   NetworkSocketAPI NetworkSocketAPI Nucleo-AWS-IoT-mbed

DnsQuery.cpp@5:d85c1a7e0e9f, 2016-02-22 (annotated)

Committer:
Christopher Haster
Date:
Mon Feb 22 19:38:10 2016 -0600
Branch:
api-changes
Revision:
5:d85c1a7e0e9f
Parent:
4:3749346dcd59
Child:
6:5b28cbc8169c
Matched changes to NetworkSocketAPI

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sarahmarshy 0:fff4b9055396 1 /* Copyright (c) 2013 Henry Leinen (henry[dot]leinen [at] online [dot] de)
sarahmarshy 0:fff4b9055396 2 *
sarahmarshy 0:fff4b9055396 3 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
sarahmarshy 0:fff4b9055396 4 * and associated documentation files (the "Software"), to deal in the Software without restriction,
sarahmarshy 0:fff4b9055396 5 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
sarahmarshy 0:fff4b9055396 6 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
sarahmarshy 0:fff4b9055396 7 * furnished to do so, subject to the following conditions:
sarahmarshy 0:fff4b9055396 8 *
sarahmarshy 0:fff4b9055396 9 * The above copyright notice and this permission notice shall be included in all copies or
sarahmarshy 0:fff4b9055396 10 * substantial portions of the Software.
sarahmarshy 0:fff4b9055396 11 *
sarahmarshy 0:fff4b9055396 12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
sarahmarshy 0:fff4b9055396 13 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
sarahmarshy 0:fff4b9055396 14 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
sarahmarshy 0:fff4b9055396 15 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
sarahmarshy 0:fff4b9055396 16 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
sarahmarshy 0:fff4b9055396 17 */
sarahmarshy 0:fff4b9055396 18 #include "DnsQuery.h"
Christopher Haster 4:3749346dcd59 19 #include <stdio.h>
Christopher Haster 4:3749346dcd59 20 #include <string.h>
sarahmarshy 0:fff4b9055396 21
sarahmarshy 0:fff4b9055396 22 //Debug is disabled by default
sarahmarshy 0:fff4b9055396 23 #if 0
sarahmarshy 0:fff4b9055396 24 #define DBG(x, ...) printf("[DNS : DBG]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 25 #define WARN(x, ...) printf("[DNS : WARN]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 26 #define ERR(x, ...) printf("[DNS : ERR]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 27 #else
sarahmarshy 0:fff4b9055396 28 #define DBG(x, ...) //wait_us(10);
sarahmarshy 0:fff4b9055396 29 #define WARN(x, ...) //wait_us(10);
sarahmarshy 0:fff4b9055396 30 #define ERR(x, ...)
sarahmarshy 0:fff4b9055396 31 #endif
sarahmarshy 0:fff4b9055396 32
sarahmarshy 0:fff4b9055396 33 #if 0
sarahmarshy 0:fff4b9055396 34 #define INFO(x, ...) printf("[DNS : INFO]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 35 #else
sarahmarshy 0:fff4b9055396 36 #define INFO(x, ...)
sarahmarshy 0:fff4b9055396 37 #endif
sarahmarshy 0:fff4b9055396 38
sarahmarshy 0:fff4b9055396 39
sarahmarshy 0:fff4b9055396 40
Christopher Haster 5:d85c1a7e0e9f 41 DnsQuery::DnsQuery(UDPSocket *sock,const char* hostname, char* ipaddress)
sarahmarshy 0:fff4b9055396 42 {
sarahmarshy 1:5d978992a518 43 socket = sock;
sarahmarshy 3:5705fdae6185 44 this->getHostByName(hostname, ipaddress);
sarahmarshy 0:fff4b9055396 45 }
sarahmarshy 0:fff4b9055396 46
sarahmarshy 3:5705fdae6185 47 bool DnsQuery::getHostByName(const char* hostname, char* resolvedIp)
sarahmarshy 0:fff4b9055396 48 {
Christopher Haster 4:3749346dcd59 49 const char * dnsIPs[] = {
sarahmarshy 2:12d08f0f20cf 50 "8.8.8.8",
sarahmarshy 2:12d08f0f20cf 51 "209.244.0.3",
sarahmarshy 2:12d08f0f20cf 52 "84.200.69.80",
sarahmarshy 2:12d08f0f20cf 53 "8.26.56.26",
sarahmarshy 2:12d08f0f20cf 54 "208.67.222.222"
sarahmarshy 2:12d08f0f20cf 55 };
sarahmarshy 0:fff4b9055396 56 for(int i = 0; i<5; i++){
sarahmarshy 2:12d08f0f20cf 57 _dnsip = dnsIPs[i];
sarahmarshy 2:12d08f0f20cf 58 if(this->getIP(hostname, resolvedIp)){
sarahmarshy 0:fff4b9055396 59 return true;
sarahmarshy 0:fff4b9055396 60 }
sarahmarshy 0:fff4b9055396 61
sarahmarshy 0:fff4b9055396 62 }
sarahmarshy 0:fff4b9055396 63 return false;
sarahmarshy 0:fff4b9055396 64
sarahmarshy 0:fff4b9055396 65 }
sarahmarshy 0:fff4b9055396 66
sarahmarshy 2:12d08f0f20cf 67 bool DnsQuery::getIP(const char* hostname, char* ipaddress)
sarahmarshy 0:fff4b9055396 68 {
sarahmarshy 0:fff4b9055396 69 INFO("%s", hostname);
sarahmarshy 0:fff4b9055396 70 int len = 0;
sarahmarshy 0:fff4b9055396 71 if (hostname == NULL)
sarahmarshy 0:fff4b9055396 72 return false;
sarahmarshy 0:fff4b9055396 73 len = strlen(hostname);
sarahmarshy 0:fff4b9055396 74 if ((len >128) || (len == 0))
sarahmarshy 0:fff4b9055396 75 return false;
sarahmarshy 0:fff4b9055396 76
sarahmarshy 0:fff4b9055396 77 int packetlen = /* size of HEADER structure */ 12 + /* size of QUESTION Structure */5 + len + 1;
sarahmarshy 0:fff4b9055396 78 char *packet = new char[packetlen]; /* this is the UDP packet to send to the DNS */
sarahmarshy 0:fff4b9055396 79 if (packet == NULL)
sarahmarshy 0:fff4b9055396 80 return false;
sarahmarshy 0:fff4b9055396 81
sarahmarshy 0:fff4b9055396 82 // Fill the header
sarahmarshy 0:fff4b9055396 83 memset(packet, 0, packetlen);
sarahmarshy 0:fff4b9055396 84 packet[1] = 1; // ID = 1
sarahmarshy 0:fff4b9055396 85 packet[5] = 1; // QDCOUNT = 1 (contains one question)
sarahmarshy 0:fff4b9055396 86 packet[2] = 1; // recursion requested
sarahmarshy 0:fff4b9055396 87
sarahmarshy 0:fff4b9055396 88 int c = 13; // point to NAME element in question section or request
sarahmarshy 0:fff4b9055396 89 int cnt = 12; // points to the counter of
sarahmarshy 0:fff4b9055396 90 packet[cnt] = 0;
sarahmarshy 0:fff4b9055396 91 for (int i = 0 ; i < len ; i++) {
sarahmarshy 0:fff4b9055396 92 if (hostname[i] != '.') {
sarahmarshy 0:fff4b9055396 93 // Copy the character and increment the character counter
sarahmarshy 0:fff4b9055396 94 packet[cnt]++;
sarahmarshy 0:fff4b9055396 95 packet[c++] = hostname[i];
sarahmarshy 0:fff4b9055396 96 } else {
sarahmarshy 0:fff4b9055396 97 // Finished with this part, so go to the next
sarahmarshy 0:fff4b9055396 98 cnt = c++;
sarahmarshy 0:fff4b9055396 99 packet[cnt] = 0;
sarahmarshy 0:fff4b9055396 100 }
sarahmarshy 0:fff4b9055396 101 }
sarahmarshy 0:fff4b9055396 102
sarahmarshy 0:fff4b9055396 103 // Terminate this domain name with a zero entry
sarahmarshy 0:fff4b9055396 104 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 105
sarahmarshy 0:fff4b9055396 106 // Set QTYPE
sarahmarshy 0:fff4b9055396 107 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 108 packet[c++] = 1;
sarahmarshy 0:fff4b9055396 109 // Set QCLASS
sarahmarshy 0:fff4b9055396 110 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 111 packet[c++] = 1;
sarahmarshy 0:fff4b9055396 112
sarahmarshy 0:fff4b9055396 113
sarahmarshy 0:fff4b9055396 114 // Ready to send to DNS
Christopher Haster 5:d85c1a7e0e9f 115 socket->setIPAddress(_dnsip);
Christopher Haster 5:d85c1a7e0e9f 116 socket->setPort(53);
sarahmarshy 1:5d978992a518 117 socket->open();
sarahmarshy 0:fff4b9055396 118
sarahmarshy 1:5d978992a518 119 INFO("Sending packet of length %d",packetlen);
sarahmarshy 1:5d978992a518 120 /*
sarahmarshy 1:5d978992a518 121 for( int i = 0 ; i < c ; i++) {
sarahmarshy 1:5d978992a518 122 printf("%02x ", packet[i]);
sarahmarshy 1:5d978992a518 123 }
sarahmarshy 1:5d978992a518 124 */
sarahmarshy 1:5d978992a518 125 if (socket->send(packet, packetlen) < 0) {
sarahmarshy 0:fff4b9055396 126 delete packet;
sarahmarshy 0:fff4b9055396 127 return false;
sarahmarshy 0:fff4b9055396 128 }
sarahmarshy 0:fff4b9055396 129 delete packet;
sarahmarshy 0:fff4b9055396 130
sarahmarshy 0:fff4b9055396 131 packet = new char [1024];
sarahmarshy 0:fff4b9055396 132
sarahmarshy 0:fff4b9055396 133 // Receive the answer from DNS
sarahmarshy 0:fff4b9055396 134 int response_length = 0;
sarahmarshy 2:12d08f0f20cf 135 INFO("Recieving");
sarahmarshy 2:12d08f0f20cf 136 response_length = socket->recv(packet, 1024);
sarahmarshy 1:5d978992a518 137 /*
sarahmarshy 1:5d978992a518 138 for( int i = 0 ; i < 1024; i++) {
sarahmarshy 1:5d978992a518 139 printf("%02x ", packet[i]);
sarahmarshy 1:5d978992a518 140 }
sarahmarshy 1:5d978992a518 141 */
sarahmarshy 2:12d08f0f20cf 142 if (response_length > 0 ) {
sarahmarshy 2:12d08f0f20cf 143 if (!resolve(packet, ipaddress)) {
sarahmarshy 2:12d08f0f20cf 144 socket->close();
sarahmarshy 0:fff4b9055396 145 delete packet;
sarahmarshy 2:12d08f0f20cf 146 ERR("NO IP FOUND\n");
sarahmarshy 2:12d08f0f20cf 147 return false;
sarahmarshy 0:fff4b9055396 148 }
sarahmarshy 2:12d08f0f20cf 149
sarahmarshy 2:12d08f0f20cf 150 // cleanup and return
sarahmarshy 2:12d08f0f20cf 151 delete packet;
sarahmarshy 2:12d08f0f20cf 152 socket->close();
sarahmarshy 2:12d08f0f20cf 153 return true;
sarahmarshy 2:12d08f0f20cf 154 } else {
sarahmarshy 2:12d08f0f20cf 155 ERR("SocketRecvFrom returned %d !", response_length);
sarahmarshy 2:12d08f0f20cf 156 }
sarahmarshy 1:5d978992a518 157 socket->close();
sarahmarshy 0:fff4b9055396 158 delete packet;
sarahmarshy 0:fff4b9055396 159 ERR("NO IP FOUND\n");
sarahmarshy 0:fff4b9055396 160 return false;
sarahmarshy 0:fff4b9055396 161 }
sarahmarshy 0:fff4b9055396 162
sarahmarshy 0:fff4b9055396 163
sarahmarshy 2:12d08f0f20cf 164 bool DnsQuery::resolve(char* resp, char* ipaddress)
sarahmarshy 0:fff4b9055396 165 {
sarahmarshy 0:fff4b9055396 166
sarahmarshy 0:fff4b9055396 167 int ID = (((int)resp[0]) <<8) + resp[1];
sarahmarshy 0:fff4b9055396 168 int QR = resp[2] >>7;
sarahmarshy 0:fff4b9055396 169 int Opcode = (resp[2]>>3) & 0x0F;
sarahmarshy 0:fff4b9055396 170 int RCODE = (resp[3] & 0x0F);
sarahmarshy 0:fff4b9055396 171 int ANCOUNT = (((int)resp[6])<<8)+ resp[7];
sarahmarshy 0:fff4b9055396 172
sarahmarshy 0:fff4b9055396 173 INFO("Resolving response : ID = %d, QR = %d, Opcode = %d, RCODE = %d", ID, QR, Opcode, RCODE);
sarahmarshy 0:fff4b9055396 174 if ((ID != 1) || (QR != 1) || (Opcode != 0) || (RCODE != 0)) {
sarahmarshy 0:fff4b9055396 175 ERR("Received non matching response from DNS !");
sarahmarshy 0:fff4b9055396 176 return false;
sarahmarshy 0:fff4b9055396 177 }
sarahmarshy 0:fff4b9055396 178
sarahmarshy 0:fff4b9055396 179 int c = 12;
sarahmarshy 0:fff4b9055396 180 int d;
sarahmarshy 0:fff4b9055396 181 // Skip domain question
sarahmarshy 0:fff4b9055396 182 while( (d=resp[c++]) != 0) {
sarahmarshy 0:fff4b9055396 183 c+=d;
sarahmarshy 0:fff4b9055396 184 }
sarahmarshy 0:fff4b9055396 185 c+= 4; // skip QTYPE and QCLASS
sarahmarshy 0:fff4b9055396 186
sarahmarshy 0:fff4b9055396 187 // Here comes the resource record
sarahmarshy 0:fff4b9055396 188 for (int ans = 0 ; ans < ANCOUNT; ans++) {
sarahmarshy 0:fff4b9055396 189 if (parseRR(resp, c, ipaddress)) {
sarahmarshy 0:fff4b9055396 190 return true;
sarahmarshy 0:fff4b9055396 191 }
sarahmarshy 0:fff4b9055396 192 }
sarahmarshy 0:fff4b9055396 193
sarahmarshy 0:fff4b9055396 194 return false;
sarahmarshy 0:fff4b9055396 195 }
sarahmarshy 0:fff4b9055396 196
sarahmarshy 2:12d08f0f20cf 197 bool DnsQuery::parseRR(char *resp, int& c, char* adr )
sarahmarshy 0:fff4b9055396 198 {
sarahmarshy 0:fff4b9055396 199 int n = 0;
sarahmarshy 0:fff4b9055396 200 while( (n=resp[c++]) != 0) {
sarahmarshy 0:fff4b9055396 201 if ((n & 0xc0) != 0) {
sarahmarshy 0:fff4b9055396 202 // This is a link
sarahmarshy 0:fff4b9055396 203 c++;
sarahmarshy 0:fff4b9055396 204 break;
sarahmarshy 0:fff4b9055396 205 } else {
sarahmarshy 0:fff4b9055396 206 c+= n; // skip this segment, not interested in string domain names
sarahmarshy 0:fff4b9055396 207 }
sarahmarshy 0:fff4b9055396 208 }
sarahmarshy 0:fff4b9055396 209
sarahmarshy 0:fff4b9055396 210 int TYPE = (((int)resp[c])<<8) + resp[c+1];
sarahmarshy 0:fff4b9055396 211 int CLASS = (((int)resp[c+2])<<8) + resp[c+3];
sarahmarshy 0:fff4b9055396 212 int RDLENGTH = (((int)resp[c+8])<<8) + resp[c+9];
sarahmarshy 0:fff4b9055396 213
sarahmarshy 0:fff4b9055396 214 INFO("Record of TYPE=%d and CLASS=%d detected !", TYPE, CLASS);
sarahmarshy 0:fff4b9055396 215 c+= 10;
sarahmarshy 0:fff4b9055396 216 if ((CLASS == 1) && (TYPE == 1)) {
sarahmarshy 2:12d08f0f20cf 217 sprintf(adr,"%d.%d.%d.%d", resp[c], resp[c+1], resp[c+2], resp[c+3]);
sarahmarshy 0:fff4b9055396 218 c+= RDLENGTH;
sarahmarshy 0:fff4b9055396 219 return true;
sarahmarshy 0:fff4b9055396 220 } else {
sarahmarshy 0:fff4b9055396 221 }
sarahmarshy 0:fff4b9055396 222 c+= RDLENGTH;
sarahmarshy 0:fff4b9055396 223
sarahmarshy 0:fff4b9055396 224 return false;
Christopher Haster 4:3749346dcd59 225 }